1. Field
Embodiments of the present disclosure relate to an electric brake system, and more particularly, to an electric brake system capable of sensing a pressure pulsation according to a request of a driver while an anti-lock brake system (ABS) operates.
2. Description of the Related Art
A brake system for braking is necessarily mounted on a vehicle, and a variety of systems for providing stronger and more stable braking have been proposed recently.
For example, there are brake systems including an anti-lock brake system (ABS) for preventing a wheel from sliding while braking, a brake traction control system (BTCS) for preventing a driving wheel from slipping when a vehicle is unintentionally or intentionally accelerated, an electronic stability control (ESC) system for stably maintaining a driving state of a vehicle by combining an ABS with a traction control to control hydraulic pressure of a brake, and the like.
Generally, an electric brake system includes a hydraulic pressure supply device which receives a braking intent of a driver in the form of an electrical signal from a pedal displacement sensor which senses a displacement of a brake pedal when the driver steps on the brake pedal and then supplies hydraulic pressure to a wheel cylinder.
An electric brake system configured with such a hydraulic pressure supply device is disclosed in European Registered Patent No. EP 2 520 473. According to the disclosure in that document, the hydraulic pressure supply device is configured such that a motor is operated according to a pedal effort of a brake pedal to generate braking pressure. At this point, the braking pressure is generated by converting a rotational force of the motor into a rectilinear movement to pressurize a piston.
Also, the electric brake system includes a simulation device capable of providing a driver with a reaction force according to the pedal effort of the brake pedal. At this point, the simulation device is connected to an oil reservoir, and a simulation valve is installed at an oil flow path which connects the simulation device to the oil reservoir. The simulation valve is provided to be blocked when the electric brake system operates abnormally and to deliver hydraulic pressure discharged from a master cylinder to the wheel cylinder such that stable braking may be performed.
Such an electric brake system has a structure in which a reaction force according to the pedal effort of the brake pedal is provided through the simulation device and the hydraulic pressure is delivered to a wheel cylinder through the hydraulic pressure supply device so that a pressure pulsation, which is generated during an ABS control, is not delivered to a driver. Therefore, although the driver requests to deliver the pressure pulsation thereto during the ABS control, a cut valve provided at a flow path, which connects a master cylinder to the wheel cylinder, should be maintained in a blocked state for stable braking so that there is a problem in that the pressure pulsation is not delivered to the driver.